WO2025046212A1

WO2025046212A1 - Apparatus and method for treatment of wastewater containing microparticles and organic molecules

Info

Publication number: WO2025046212A1
Application number: PCT/GB2024/052089
Authority: WO
Inventors: Lee Underwood; Bethany CAMPBELL
Original assignee: VWS (UK) Limited
Priority date: 2023-08-31
Filing date: 2024-08-08
Publication date: 2025-03-06
Also published as: GB202313301D0

Abstract

A clinical wastewater treatment apparatus to treat a clinical wastewater effluent stream, comprising: a filter unit having - a clinical wastewater effluent stream inlet, - a fluid outlet, and - a disposable waste container, fluidly connected in use to the clinical wastewater effluent stream inlet and the fluid outlet, and having a micron waste filter within the filter unit; a pump fluidly connected to the filter unit outlet; a sub-micron waste filter fluidly connected to the pump, and able to provide a retentate stream and a filtered water stream; and a recirculation pathway to pass the retentate stream into the filter unit, such that the retentate stream passes through the micron waste filter.

Description

Apparatus and method for treatment of wastewater containing microparticles and organic molecules

The present invention relates to apparatus and a method for treatment of wastewater containing microparticles and organic molecules, particularly but not exclusively wastewater from clinical analysers.

Background

Clinical analysers are well known in the art, generally being medical laboratory instruments able to analyse a sample, generally a medical sample, to determine one or more characteristics in or for a clinical purpose. One example is an analyser able to measure the properties of bodily fluids such as blood or urine, to assist in diagnosis of a condition or disease of a patient. To enable such determination, the analyser uses various known reagent chemicals which are provided by the analyser manufacturer.

Clinical analysers are used to process a large portion of the samples going into a hospital or private medical laboratory. In the US, such apparatus are regulated under the Code of Federal Regulations (CFR) Title 21 , in particular Part 862. Section 862.2150 defines a continuous flow sequential multiple chemistry analyser for clinical use.

Clinical analysers generally use one or more water streams, often being purified or indeed ultra-purified water, in the processing and analysis of samples, and/or for cleaning of reaction vessels, tubing and sample holders, etc. The or each resultant water stream or streams, or ‘effluent(s)’, after such use is or are termed the ‘wastewater’. Where there are multiple resultant streams, each stream can be dealt with separately, but may be combined together to form a single wastewater stream. Due to the use of alkaline solutions, such as sodium hydroxide in the processes of the analyser, the wastewater is often of high pH.

With increasing health and safety legislation and increased local regulation, clinical analyser wastewater is increasingly unable to be simply discharged to the municipal drain, but must instead be collected for off-site disposal typically by incineration, or is increasingly required to be fully or partially treated on or off site.

Examples of apparatus to treat clinical wastewater are LIS9611160, and WO2021/048524 and EP2765118A, which discloses a clinical analyser wastewater treatment apparatus comprising a carbonator section, an anodic oxidation section, a heavy metal removal section, a UV disinfection section, a pH sensor and/or a conductivity sensor, and a recirculation after the UV disinfection section to before the carbonator section.

Microparticles are used in clinical analysers to deliver certain essential test components such as enzymes to the analyser to carry out the tests required on the patients’ blood or other material. Microparticles is a term including microplastics. Microplastics are defined by the European Chemical Agency (ECHA) as being typically less than 5 mm. Once in the environment they do not biodegrade and accumulate in fish, shellfish and animals and consequently end up in the human food chain.

As the effects of microparticles on the environment are becoming increasingly understood, regulation is being proposed for limiting the use of microparticles, and where use is required, to limit or prevent their reaching the natural environment.

Due to the practicality of analysing the smallest particles, a lower limit for the regulation of 1nm with an intermediate temporary limit of 100nm has been proposed to enable analysis for enforcement purposes, although the desire is complete removal of microplastics.

The health effects of non-plastic microparticles have also become more known in recent years as exemplified by the bans on the use of asbestos. Further knowledge and restrictions on other non-plastic microparticles are likely to occur.

Microparticles used in clinical analysers are often polystyrene based, but some may have iron based cores and as such are magnetic. There is unlikely to be a replacement methodology for this process in the near future, so that the waste and wash from the analyser requires treating to remove the used microparticles from the waste and to prevent them entering the environment. Microparticles used in clinical analysers are typically in the range of 50 nm - 10 urn.

Clinical analyser wastewater contains the remnants of the biological samples that have been tested in the analyser and as such they may be considered as a biohazard, and any material coming into contact with the wastewater may also be considered as potentially being contaminated and may therefore be required to be considered as medical or clinical waste and may be subject to regulation regarding its disposal.

It is therefore now expected that any treatment of clinical wastewater should be carried out in such a manner that protects all operatives in the laboratories, whether they are clinical analyser operatives or engineers servicing the clinical analyser wastewater treatment device.

It is an object of the present invention to provide an improved apparatus and method for the treatment of clinical analyser wastewater containing microparticles and organic molecules.

Summary

According to a first aspect of the present invention, there is provided a clinical wastewater treatment apparatus to treat a clinical wastewater effluent stream, comprising: a filter unit having

- a clinical wastewater effluent stream inlet,

- a fluid outlet, and

- a disposable waste container, fluidly connected in use to the clinical wastewater effluent stream inlet and the fluid outlet, and having a micron waste filter within the filter unit; a pump fluidly connected to the filter unit outlet; a sub-micron waste filter fluidly connected to the pump, and able to provide a retentate stream and a filtered water stream; and a recirculation pathway to pass the retentate stream into the filter unit, such that the retentate stream passes through the micron waste filter. According to a second aspect of the present invention, there is provided a method of treating a clinical analyser wastewater effluent stream containing microparticles and organic molecules, comprising at least the following steps in any order:

(a) providing a clinical wastewater treatment apparatus comprising a filter unit, said unit having a disposable waste container having a micron waste filter therein;

(b) filtering the clinical analyser wastewater effluent stream through the micron waste filter to capture organic molecules, and to provide a filtered clinical analyser wastewater stream;

(c) pumping the filtered clinical analyser wastewater stream through the filter unit outlet to a sub-micron waste filter;

(d) filtering the filtered clinical analyser wastewater stream through the sub-micron waste filter to provide a retentate stream and a filtered water stream; and

(e) recirculating the retentate stream into the waste container to pass through the micron waste filter.

According to a third aspect of the present invention, there is provided a method of collecting and disposing of organic molecules and microparticles in a clinical analyser wastewater effluent stream, comprising at least the steps of:

(a1) passing an initial clinical analyser wastewater effluent stream into a clinical wastewater treatment apparatus, said apparatus having a sealable and disposable filter unit having a micron waste filter therein;

(b1) pumping the clinical analyser wastewater stream or a filtered clinical analyser wastewater stream through the filter unit outlet to a sub-micron waste filter;

(c1) filtering the clinical analyser wastewater stream or filtered clinical analyser wastewater stream through the sub-micron waste filter to provide a retentate stream and a filtered water stream;

(d1) circulating or recirculating the retentate stream into the filter unit to pass through the micron waste filter;

(e1) filtering the retentate stream through the micron waste filter to provide a filtered clinical analyser wastewater stream;

(f1) passing the filtered water stream of step (c1) to a drain;

(g1) repeating steps (b1) to (f1); (hi) determining an end use of the filter unit and stopping the pump; and

(i1) detaching and sealing the filter unit from the clinical wastewater treatment apparatus for disposal.

According to a fourth aspect of the present invention, there is provided a method of collecting and disposing of organic molecules and microparticles in a clinical analyser wastewater effluent stream using the clinical wastewater treatment apparatus as defined herein.

Description of the Drawings

Embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawings in which:

Figure 1 shows a schematic view of a clinical analyser wastewater treatment apparatus according to a first embodiment of the present invention;

Figure 2 shows a more detailed cross section of the filter unit and waste container of the arrangement of Figure 1;

Figure 2a is a plan view of Figure 2;

Figure 2b is a schematic side view of the filter unit of Figure 2 as a second embodiment of the present invention;

Figure 3 shows an anodic oxidation cell that may be used in an embodiment of the present invention;

Figures 4a and 4b show alternative UV irradiation chambers that may be used in an embodiment of the present invention;

Figure 5 shows a gas/liquid contactor that may be used in an embodiment of the present invention; and

Figure 6 shows a foam fractionation device that may be used in an embodiment of the present invention.

Detailed description

The present invention relates to a clinical wastewater treatment apparatus to treat a clinical wastewater effluent stream, comprising: a filter unit having - a clinical wastewater effluent stream inlet,

- a fluid outlet, and

- a disposable waste container, fluidly connected in use to the clinical wastewater effluent stream inlet and the fluid outlet, and having a micron waste filter within the filter unit; a pump fluidly connected to the filter unit outlet; a sub-micron waste filter fluidly connected to the pump, and able to provide a retentate stream and a filtered water stream; and a recirculation pathway to pass the retentate stream into the filter unit, such that the retentate stream passes through the micron waste filter.

The term “clinical analyser” as used herein relates to any apparatus, unit or instrument able to analyse a clinical, medical or biological sample, usually in an automated manner, and commonly in a multiple batch process, in order to measure or define one or more characteristics of or within the sample, such as the presence and/or amount of certain chemical or biological substances, such as particular markers or cells or the like. Suitable examples include the analysis of blood or other bodily fluids. In the US, such clinical analysers can be defined under CFR21 Part 862.

The term “wastewater effluent” as used herein relates to one or more of the discharges or effluents from a clinical analyser which include one or more substances not considered environmentally safe for direct discharge into a drain or other non-clinical water system. Such substances include, but are not limited to, ions including azide ions, organics, biochemical reagents, heavy metals, heavy metal complexes, inorganic salts, inorganic reagents, and any other chemically or biologically active bodies, microplastics and microparticles.

The clinical wastewater treatment apparatus of the present invention comprises at least one outlet, optionally a plurality of outlets. Optionally, at least one outlet of the treatment apparatus provides a discharge, line or passage to a drain, optionally a non-dedicated drain within the environment of the clinical analyser, for the filtered water stream. The clinical analyser wastewater treatment apparatus may be constructed within a single housing or chassis containing at least a space, area or chamber into which the filter unit containing the micron waste filter may be placed and operated.

Optionally, the clinical wastewater treatment apparatus further comprises a first bunded housing to support the filter unit, and wherein the filter unit is separable from the first bunded housing. The first bunded housing may be rigid, semi-rigid, or at least self-supporting. As well as housing the filter unit, the filter housing can further prevent any clinical wastewater effluent coming into contact with users, and can also safely contain hazardous wastewater should there be any leak or other failure in the integrity of the filter unit.

The first bunded housing may have any suitable size, shape and design, generally being in the form of a box or box-shape with an open top, having the clinical wastewater effluent stream inlet and a filter unit outlet at or near the top of the box, with the filter unit supported in use by the bottom or base of the first bunded housing in use.

Optionally, an upper face, side, surface or covering of the first bunded housing is moveable, removable, hinged or slidable relative to the remainder of the housing to allow for easier insertion and removal of the filter unit with the housing. Such an upper surface may be a lid or a portion thereof of the housing.

Optionally, an upper surface of the first bunded housing has an aperture or cutaway to help locate a filter unit therewith.

Optionally, the filter unit and at least an upper surface of the first bunded housing have means to attach together. Such attachment may be sliding slots or grooves, use of location pins, or other attaching devices or methods as known in the art.

Optionally, the filter unit includes a filter unit manifold having the clinical wastewater effluent stream inlet and the fluid outlet. Optionally, the treatment apparatus has a treatment apparatus manifold having ports to match with the filter unit manifold. The filter unit manifold may be integral or separate from the filter unit.

In one embodiment, the filter unit includes a filter unit manifold at or near a top or upper end, and the treatment apparatus has a complementary treatment apparatus manifold to provide easy connections to at least a clinical wastewater inlet, a fluid outlet and a recirculation pathway as described herein. The complementary nature of the manifolds allow a clinical wastewater effluent stream inlet, a fluid outlet and a recirculation pathway as described herein to engage easily and quickly with a filter unit in use, whilst also providing a safe manner for detachment of the filter unit after use.

Optionally, the filter unit includes a securing means to maintain the filter unit manifold and the treatment apparatus manifold together, especially during use. Securing means include interlocking means, such as spigots and pins, as well as a securing collar. Optionally, the securing means also secures at least the filter unit manifold to the waste container.

Optionally, the waste container has a first threaded seal with the filter unit manifold to secure the waste container and the filter unit manifold together.

Optionally, the waste container has a second threaded seal with either a manifold securing collar or a blanking cap.

Optionally, the first threaded seal or the second threaded seal, or both, are located in or around the circumference of an upper, top or neck portion of the waste container. Optionally, the first threaded seal and the second threaded seal are axially offset.

In this way, the treatment apparatus manifold can be removed for connection with the next filter unit, whilst the filter unit manifold can be sealingly retained with the filter unit after use, and when being disposed of as clinical waste.

Optionally, a manifold securing collar is replaceable by a blanking cap; such as for delivery of the apparatus, and/or once a filter unit is detached from the treatment apparatus manifold, so as to maintain biosecurity of the contents of the filter unit prior to its disposal. Optionally, the blanking cap caps the ports of the filter unit manifold.

Optionally, the clinical wastewater treatment apparatus further comprises a second bunded housing to house the pump and the sub-micron waste filter. In this way, the second bunded housing can prevent filtered clinical wastewater effluent coming into contact with users, and can also safely contain hazardous wastewater should there be any failure in the pump or the sub-micron waste filter or the connections into and out thereof.

The second bunded housing may have any suitable size, shape and design, generally being in the form of a bucket or box, having one or more inlets and one or more outlets at or near the top.

Optionally, the first bunded housing or the second bunded housing or both such housings, has lifting handles.

Optionally, the filter unit has lifting handles to assist handling and relocation of the filter unit.

Lifting handles allow a user to relocate the filter unit/first bunded housing/second bunded housing to another environment, such as a better biosecurity environment, such as when removing the filter unit and placing it into a labelled bag for safe disposal such as by incineration, or if a leak has occurred in any of the filter unit/first bunded housing/second bunded housing.

Optionally, the clinical wastewater treatment apparatus further comprises a recirculation pathway for the retentate to return to the filter unit. In this way, the retentate can be recirculated back to the inlet of the filter unit, for re-filtration therethrough.

In use, the apparatus of the present invention can be used in a continuous manner or a batch manner. For example, the apparatus can achieve a ‘steady state’ of inlet water from one or more clinical analysers, and a filtered water stream product or be operated intermittently as required by the schedule of waste generated by the clinical analyser. Alternatively or additionally, the apparatus can be filled with a desired volume, and the retentate re-circulated until a desired outcome is achieved, such as a desired cleaning time, level, or quality of a final water stream or waste within the container.

The term “clinical wastewater effluent stream inlet” as used herein includes receiving clinical wastewater effluent streams from one or from more than one clinical wastewater analyser, either in parallel or collectively.

Optionally, the clinical wastewater effluent stream inlet and the filter unit outlet are part of or connectable through a treatment apparatus manifold. The treatment apparatus manifold may be a single moulding, which is separate, detachable or integral with the clinical wastewater treatment apparatus.

Optionally, the filter unit has a filter unit manifold able to connect to the clinical wastewater effluent stream inlet and the filter unit outlet. The filter unit manifold may be separate, detachable or integral with the filter unit. In one embodiment, the filter unit manifold is integral with the filter unit when in use.

Optionally, the flow connections to the filter unit are such that when the filter unit is detached from the remainder of the filter unit, no material from inside the filter unit can pass to outside the filter unit.

Optionally, the fluid connections between the filter unit and the remainder of the clinical wastewater treatment apparatus, are sealable upon detaching the filter unit from the treatment apparatus. Various sealing ports, including self-sealing ports are known in the art, and may be a valve or face able to seal the port upon detachment of the two parts. Self-sealing also may be performed using memory materials, springs, levers, magnets or any other known methodology.

Optionally, the connections into and out of the filter unit are such that they are open when the filter unit is inserted in its place of operation for use, and self-sealing when the connections are removed post-use. In one embodiment of the present invention, the clinical wastewater effluent stream inlet and the filter unit outlet are part of a treatment apparatus manifold, and the filter unit has a complementary filter unit manifold able to connect to the treatment apparatus manifold, wherein the fluid connections between the treatment apparatus manifold and the filter unit manifold are sealable upon detaching the filter unit from the treatment apparatus.

Optionally in such an embodiment, either the treatment apparatus manifold or the filter unit manifold or both include sealable valves.

The filter unit may be rigid, flexible or semi-flexible, and have a differing shape between an in-use configuration and a post-use configuration. The in-use configuration relates to the passage and filtering of a clinical wastewater effluent stream therethrough, and the post-use configuration relates to the operations for replacement of the filter unit as described herein.

Optionally, the filter unit further includes an internal outlet feed for the fluid outlet of the filter unit, the internal outlet feed having a porous filter. The outlet feed may be in the form of a draw tube, able to provide a fluid conduit to the outlet of the filter unit. Such an outlet feed may extend partly or substantially into the filter unit.

The term “conduit” as used herein includes any pipe, tube or other known means of transferring liquids between locations.

Optionally, the porous filter is a foam filter in the path of the filter unit outlet.

Optionally the porous filter is a millimetre or sub-millimetre foam filter having a pore size in the range 100 -1000 pm.

Optionally, the filter unit has an in-use configuration volume in the range of 2-20 litres, such as 5 litres or 10 litres or the like.

Optionally, the waste container is a plastics material selected from the group comprising: polyethylene (PE), polypropylene (PP), acrylic, polycarbonate, polyvinyl chloride, polyethylene terephthalate, acrylonitrile butadiene styrene, and combinations of same. Plastics materials can be provided in various ‘grades’. For example, PE is categorized into five groups: low-density polyethylene (LDPE), high- density polyethylene (HDPE), linear low-density polyethylene (LLDPE), very-low- density polyethylene (VLDPE), and ultra-high-molecular-weight polyethylene (UHMWPE).

Optionally, the waste container is strong enough to take the pressure of its contents in use, as well as being chemically resistant to those chemicals. The strength of the waste container may be related to its thickness. PE and PP can be provided in a range of thicknesses. The thickness of material is typically in the range 0.1 -1.0 mm

The term “micron waste filter” as used herein relates to any porous screen or mesh structure designed to prevent the passage of particles by size exclusion.

Optionally, the micron waste filter comprises a woven or a mesh material.

Optionally, the woven or mesh material is selected from the group comprising: polyethylene (PE), polypropylene (PP), nylon, acrylic, polycarbonate, polyvinyl chloride, polyethylene terephthalate, acrylonitrile butadiene styrene, and combinations of same. One particular material is PP.

Optionally, the micron filter comprises a mesh material having a pore size in the range of 1-1000 pm or micron, preferably 10-100 pm, and including but not limited to a pore size of 20 pm, 30 pm, 40 pm, 50 pm, 60 pm, 70 pm and 80 pm.

Optionally, the filter unit further comprises a pressure relief valve between the internal and external sides of the micron waste filter. The pressure relief valve allows the relief of any pressure build up within the micron filter, or within the inlet side of the micron filter. This may occur where the micron waste filter is losing its efficiency or capacity, for example getting blocked by the waste material it is collecting.

Optionally, the filter unit is detachable from the remainder of the treatment apparatus, and the filter unit is thereafter disposable as clinical waste. As such, the present invention provides a detachable and disposable filter unit having a micron waste filter within the filter unit, wherein the filter unit has a first port being fluidly connectable to a clinical wastewater effluent stream inlet of a clinical wastewater treatment apparatus able to treat a clinical wastewater effluent stream, and a second port being fluidly connectable to a filter unit outlet of the clinical wastewater treatment apparatus.

Embodiments described herein in relation to the clinical wastewater treatment apparatus apply equally to embodiments for the sealable and detachable filter unit of the present invention.

The filter unit of the present invention is able to provide a filtered stream through the filter unit outlet to a downstream pump fluidly connected to the filter unit outlet, and a sub-micron waste filter fluidly connected to the pump able to provide a retentate and a filtered water stream.

The filter unit of the present invention is useable in the clinical wastewater treatment apparatus as defined herein.

Optionally, the present invention further comprises means to determine the efficiency of the filter unit or sub-micron waste filter over time. The filter unit or sub-micron waste filter efficiency can be measured by one or more qualities, quantities or attributes of the apparatus or a part of the apparatus, either continuously, regularly, or otherwise, over time. Such attributes include one or more physical or chemical measurements, either of the filter unit or sub-micron waste filter itself, or downstream thereof, or of an aspect of the clinical wastewater treatment apparatus. Such measurements can be one or more of the group comprising: weight or load, water pressure, flow rate, quality of retentate, density, light or other waveform reflection or penetration, and colour.

Thus, the means to determine the status or efficiency of the filter unit or sub-micron waste filter over time include one or more load cells, spectrometers, reflectometers, sensors, flow sensors, pressure sensors, water quality sensors, etc.

Optionally, the apparatus of the present invention includes a device for measuring the pressure of the flow from the pump. Optionally, the apparatus of the present invention includes a device for measuring the weight of the filter unit over time.

In one embodiment of the present invention, the clinical wastewater treatment apparatus further comprises a weighing device to measure the weight of the filter unit over time, such as one or more load cells located under the filter unit.

In another embodiment of the present invention, the clinical wastewater treatment apparatus further comprises a pressure sensor to measure the water pressure at one or more locations in the apparatus over time, to determine the effectiveness of the micronwaste filter, and hence changing resistance to water flow therethrough.

The sub-micron waste filter is able to filter microparticles from a filter stream. The term “sub-micron waste filter” as used herein relates to micro-filters, nano-filters, ultra-filters or hyper-filters with pore sizes of less than 10 micrometres. Optionally, the sub-micron waste filter is a sub-micron waste filter of pore size 0.01 to 10 micrometres.

One sub-micron waste filter design comprises hollow fibre membranes where multiple membrane fibres are in a housing and feed flows through the lumen of the fibres with filtrate passing through the fibre to be collected on the outside or shellside of the fibres and from where it passes from the housing as a permeate stream.

An alternative sub-micron waste filter design is to have sheets of membrane wound in a spiral. Feed water passes from one end of the spiral to the other along the channel formed by the windings, the windings being held apart by spacer materials. The water is filtered as it passes through the sheet with the molecules larger than the pore size of the membrane remaining in the water on the feed side of the membrane while the filtered water having passed through the membrane is collected in a central channel and then passes out of the sub-micron waste filter.

Optionally, the sub-micron waste filter comprises a spiral wound membrane or a hollow fibre membrane. The term “microparticles” as used herein includes microplastics. As mentioned above, microplastics are defined by the European Chemical Agency (ECHA) as being typically less than 5 mm. Due to the practicality of analysing the smallest particles, a lower limit for the regulation of 1nm with an intermediate temporary limit of 100nm has been proposed to enable analysis for enforcement purposes, although the desire is for complete removal of microplastics. Microparticles used in clinical analysers are typically in the range of 50 nm - 10 urn.

Optionally, the filter unit further comprises a filtered vent, to allow a stable pressure to be maintained within the waste container during changes in the liquid volume in the waste container. Optionally, the vent includes a hydrophobic membrane to prevent water passing through it. Optionally the vent may contain material or filters to prevent biologically active material from entering the atmosphere. Optionally the vent may contain material, such as activated carbon, to remove molecules that are noxious or harmful and prevent them from entering the atmosphere outside the apparatus.

Optionally, the filter unit is disposable as clinical waste after detachment from the remainder of the clinical wastewater treatment apparatus. This may entail placing the filter into a specific bag of a specified colour and labelled for disposal by means specified in regulations.

Optionally, the micron waste filter has an elongate shape having an inner feed side. Optionally, the micron waste filter is in the form of a filtration bag able to maintain integrity whilst holding an increasing weight of trapped or captured particles. Optionally the waste filter has a single sheet or welded seam construction.

Optionally, the clinical wastewater treatment apparatus further includes a downstream ultraviolet disinfection unit, such as an ultraviolet irradiation chamber, able to inactivate any bioactive material in the filtrate from the sub-micron waste filter prior to its passing to the filtered water outlet. Suitable UV devices are described in W02020/035666, incorporated herein by reference. Optionally, the clinical wastewater treatment apparatus further includes a downstream ultraviolet oxidation unit to oxidise organic molecules that may be in the filtrate from the sub-micron waste filter prior to its passing to the filtered water outlet.

Optionally, the clinical wastewater treatment apparatus further includes a downstream anodic oxidation unit or chamber. An anodic oxidation unit or chamber is able to oxidise organic molecules that may be in the filtrate from the sub-micron waste filter prior to its passing to the filtered water outlet.

Optionally the clinical wastewater treatment apparatus further includes using the anodic oxidation chamber or ultraviolet oxidation unit to destroy azide from the submicron membrane filtrate.

The term “anodic oxidation” as used herein relates to the action that can be provided by an electrochemical cell in a chamber comprising one or more anodes and one or more cathodes. A fluid path from an inlet into the chamber allows the fluid to be treated to flow between the electrodes to an outlet of the chamber. The reactions at the anode result in generation of oxidising species such as ozone, peroxide, peroxide radicals and oxygen radicals which react with the molecules in the wastewater breaking them down. The choice of anode material is important in deciding which reactions at the anode occur and it is preferable to use a boron doped diamond electrode as this generates species that oxidise bonds in organic molecules breaking them down into smaller molecules and eventually to small molecules including carbon dioxide and water.

Anodic oxidation may also be used to remove azide from the wastewater. As azide is a small molecule it will pass into the filtered water from the sub-micron waste filter and anodic oxidation has been shown to effectively destroy azide.

Thus, the present invention may comprise passing the filtered water, generally as a stream, through an anodic oxidation chamber having an anodic oxidation cell including a conductive diamond anode, preferably a boron doped diamond electrode, to oxidise the organic molecules or azide ions in the stream, and to reduce the organic molecule or azide ion concentrations such that the concentration of organic molecules or azide ions in the post-chamber treated water stream is less than the concentration of organic molecules and azide ions in the wastewater entering the chamber.

Recirculation around the anodic oxidation chamber allows for repeated and thus greater treatment of the water or allows the use of smaller apparatus.

Further description of anodic oxidation devices can be found in WO2012/09328, incorporated herein by reference.

Optionally, the clinical wastewater treatment apparatus further includes a downstream gas/liquid pH adjustment unit, to adjust the pH of the filtrate from the sub-micron waste filter prior to its passing to the filtered water outlet. Preferably a gas/liquid contactor as known in the art is used to reduce the pH of the wastewater to a desired level. Optionally the gas/liquid contactor further includes the passing of air or carbon dioxide to the gas side of the gas/liquid contactor.

Further description of use of gas/liquid pH adjustment units can be found in GB2510564, incorporated herein by reference.

Optionally, the clinical wastewater treatment apparatus further includes a downstream foam fractionation unit, able to fractionate away a foam formed from the filtered water, to further reduce impurities in the filtered water stream in a manner known in the art.

The present invention also includes a method of treating a clinical analyser wastewater effluent stream containing microparticles and organic molecules, comprising at least the following steps in any order:

(c) pumping the filtered clinical analyser wastewater stream through the filter unit outlet to a sub-micron waste filter; (d) filtering the filtered clinical analyser wastewater stream through the sub-micron waste filter to provide a retentate stream and a filtered water stream; and

Optionally, the method further comprises the step of passing the filtered clinical analyser wastewater stream through a porous filter within the waste container, prior to step (c).

Optionally, the method further comprises prior to any of steps (b) to (e), the step of initially passing the clinical analyser wastewater effluent stream into the filter unit through a clinical wastewater effluent stream inlet to partly, substantially or wholly fill the filter unit.

Optionally, the method further comprises the step of further filling the filter unit with a clinical analyser wastewater effluent stream during any one or more of steps (b) to (e).

Optionally, the operation of the pump in step (c) is dependent on the volume, the weight, or both the volume and weight, of the clinical analyser wastewater stream in the filter unit.

Alternatively and/or additionally, the operation of the pump in step (c) may be dependent on the pressure of the flow from the pump.

Optionally, the method further comprises determining the capacity of the filter unit over time.

Optionally, the method of the present invention comprises repeating steps (b) to (e) until the capacity of the filter unit reaches a pre-determined value, and then further comprising the steps of;

- stopping the pump, - detaching the filter unit from the clinical wastewater treatment apparatus,

- optionally adding a blanking cap onto the filter unit, and

- disposing of the filter unit as clinical waste.

Optionally, the method further comprises determining the capacity of the filter unit over time by either measuring the pressure of the flow from the pump, or measuring the weight of the filter unit over time, or both.

Optionally, the method further comprises treating the filtered water stream with one or more of the following in any order: ultraviolet irradiation, anodic oxidation, gas/liquid pH adjustment, and foam fractionation.

Optionally, the pH adjustment comprises passing air or carbon dioxide to the gas side of a gas/liquid contactor as described herein.

Optionally, the method comprises the step of treating the filtered water stream with foam fractionation, by forming and then removing a foam in the filtered water, to further reduce impurities in the filtered water stream in a manner known in the art. Forming a foam typically involves passing a gas such as air through the filtered water stream. Such foam is typically separated or relocated to either another treatment subsystem, or exited from the clinical wastewater treatment apparatus. Optionally, once separated or relocated, a foam destabilisation material may be included to break down the foam and thereby reduce its volume.

Optionally, the method comprises the step of treating the filtered water stream with two or three of the ultraviolet irradiation, anodic oxidation, gas/liquid pH adjustment, and foam fractionation described herein.

Optionally, the method further comprises using the clinical wastewater treatment apparatus as defined herein.

The present invention also extends to collecting and disposing of organic molecules and microparticles in a clinical analyser wastewater effluent stream, comprising at least the steps of: (a1) passing an initial clinical analyser wastewater effluent stream into a clinical wastewater treatment apparatus, said apparatus having a sealable and disposable filter unit having a micron waste filter therein;

(f1) passing the filtered water stream of step (c1) to a drain;

(g1) repeating steps (b1) to (f1);

(hi) determining an end use of the filter unit and stopping the pump; and

(i1) detaching and sealing the filter unit for disposal.

Optionally, the method further comprises the step of passing the filtered clinical analyser wastewater stream through a porous filter within the filter unit, optionally wherein the porous filter is a millimetre or sub-millimetre foam filter having a pore size in the range 100 -1000 pm, prior to step (b1).

Optionally, the method further comprises the step of replacing the detached filter unit with a new filter unit.

Optionally, the method further comprises measuring the capacity of the filter unit and/or the porous filter over time, and operating step (b1) according to the capacity of the filter unit.

Optionally, the method further comprises measuring the weight of the filter unit, and operating step (b1) according to the weight of the filter unit.

Optionally, the method further comprises using the weight measurement of the filter unit to determine the operation of step (hi). Optionally, the method further comprises using the clinical wastewater treatment apparatus as defined herein.

Optionally, the method further comprises the step of detaching the filter unit from the clinical wastewater treatment apparatus as described herein.

Optionally, the filter unit is sealable when detached from the remainder of the clinical wastewater treatment device or apparatus.

Thus, in one embodiment of the present invention, the method in operation comprises a clinical analyser wastewater stream entering the clinical analyser wastewater treatment apparatus, wherein it is passed into the filter unit, and presented to the inside or feed side of the micron waste filter. The wastewater flows through the micron waste filter and any larger particles are caught within the pores or on the surface of the micron waste filter. The water that has passed through the micron waste filter is drawn up a suitable pathway such as a conduit or tube, by the action of the pump, such as a positive displacement pump, connected to the filter unit, and passed to a sub-micron waste filter, which splits the wastewater into a retentate containing the particles and larger organic molecules and a permeate containing only smaller molecules. The filtered permeate is passed for further treatment as detailed herein or passed from the unit to drain. The retentate can be returned to the filter unit on the feed side of the micron waste filter.

Alternatively the clinical analyser wastewater stream may be fed into another section of the recirculation loop.

As the clinical waste is retained by the filter unit a suitable filter unit status sensor such as a load cell, can initiate a measuring operation of the weight of the filter unit and when a maxima or defined level is reached the clinical wastewater treatment apparatus can indicate the need to change the filter unit. The status sensor may also be used to cease operation when it reaches another defined limit such as when there is no change in the force upon the load cell, and hence no further permeate being produced during treatment. Alternatively, flow measuring or pressure sensing devices may be used to indicate this occurrence in methods known in the art.

As the retentate is recirculated the concentration of larger molecules such as proteins increases and, as the concentration exceeds the solubility of the molecules, they become insoluble and therefore more likely to be removed as the water passes through the filter unit. As the organic molecules are removed there is an increasing likelihood of surface attractions causing the microparticles to become captured within the precipitate being formed on the surface and in the pores of the micron waste filter.

It is possible to operate the recirculation with a flush of the liquid in the pathway or recirculation loop prior to producing permeate. This will help to remove any particles that may be on the retentate side of the membrane of the sub-micron waste filter, or flush out any air that may have come out of solution.

It is possible to operate the recirculation with a settle period by stopping the recirculation. This may allow for material collecting on the surface of the porous filter or micron waste filter in the filter unit to drop to the bottom of the filter unit and may allow particles being held in the sub-micron waste filter, for example against a submicron waste filter membrane, to ease away from the surface, making it easier to flush them out of the sub-micron waste filter and return them to the filter unit.

Combining these operation modes leads to a preferred in use operation sequence of flush, treat and settle being carried out repeatedly.

As material is removed by the micron waste filter, an attribute of the micron waste filter, such as the mass of the micron waste filter, will change. For example, the mass will increase, and this increase can be measured by a load cell. It is optional to record the force on the load cell when the filter unit is at its maximum liquid content or at its minimum liquid content. The increase in these values over time may be logged and when the increase reaches a pre-defined amount the unit may indicate that the filter unit requires changing. Either when indicated or at set periods, such as specified by a service schedule, the filter unit can then be replaced. The amount of fluid in the filter unit is reduced to a minimum by operation of the apparatus as described herein, without new clinical wastewater entering the apparatus. The feeds and the outlets from the filter unit are removed, optionally with a single action to separate the manifolds and preferably in a way that the ports in the filter unit seal preventing release of any fluid to the environment. The filter unit can then be placed into such clinical waste bag or other receptacles as specified by local legislation and practice and disposed of by methods, such as incineration, as locally specified.

Thus, the present invention extends to a method of collecting and disposing of organic molecules and microparticles in a clinical analyser wastewater effluent stream, comprising at least the steps of:

(a) passing the clinical analyser wastewater effluent stream into a clinical wastewater treatment apparatus having a clinical wastewater effluent stream inlet, a filtered water outlet, and a sealable, detachable and disposable filter unit fluidly connected to the clinical wastewater effluent stream inlet;

(b) filtering the clinical analyser wastewater effluent stream through a micron waste filter within the filter unit to provide a first filtered clinical analyser wastewater stream;

(c) pumping the first filtered clinical analyser wastewater stream through the filter unit outlet to a downstream sub-micron waste filter;

(d) filtering the first filtered clinical analyser wastewater stream through the submicron waste filter to provide a retentate and a filtered water stream; and

(e) detaching and sealing the filter unit from the clinical wastewater treatment apparatus.

Optionally, the method further comprises the step of self-sealing the filter unit as described herein when being detached from the clinical wastewater treatment apparatus.

Optionally, the method further comprises the step of replacing the detached filter unit with a new filter unit. Optionally, the method further comprises measuring the efficiency of the filter unit ver time as described herein, and operating step (c) according to a measurement of the filter unit . For example, the method comprises measuring the weight of the filter unit, and operating step (c) according to the weight of the filter unit as described herein.

Optionally, the method further comprises the step of ceasing step (a) and maintaining steps (b) and (c) prior to step (e). Optionally, the waste container is flexible between an expanded in-use configuration described herein during steps (a)- (d), and a contracted post-use configuration as described herein after ceasing step (a) and maintaining steps (b) and (c) prior to step (e).

Optionally, the method further comprises the step of recirculating the retentate in step (d) through the filter unit as described herein.

Optionally, the method further comprises the step of ceasing step (a) and maintaining steps (b) and (c) and the recirculating of the retentate until the filtered water stream diminishes prior to step (e). In this way, the filter unit is drained of water prior to replacement to minimise its weight, and so to minimise the amount of waste needing to be incinerated.

Optionally, the method further comprises using the weight measurement of the filter unit to determine the operation of step (c), in particular the operation, typically the speed, of a suitable pump for the pumping.

Optionally, a new filter unit and micron waste filter are then fitted to the clinical wastewater treatment apparatus, so that the method can be restarted.

Optionally, the step of detaching and sealing the filter unit from the remainder of a clinical wastewater treatment apparatus comprises disengagement of complementary manifolds as described herein for the filter unit and the apparatus as described herein.

Referring to the drawings, Figure 1 shows a simplified schematic diagram of one embodiment of the present invention. Figure 1 shows a clinical analyser wastewater treatment apparatus 10 comprising a filter unit 11 having a clinical wastewater effluent stream inlet 22, a filter unit outlet 26, and a disposable waste container 12. The filter unit 11 has a micron waste filter 15 within the disposable waste container 12. The apparatus 10 also comprises a pump 30 fluidly connected to the filter unit outlet 26 via a pump feed conduit 28, and a sub-micron waste filter 36 fluidly connected to the pump 30. The sub-micron waste filter 36 is able to provide a retentate stream to a retentate conduit 46 and a filtered water stream to a filtered water conduit 40. The apparatus 10 also comprises a recirculation pathway including the retentate conduit 46 to pass the retentate stream into the filter unit 11 , such that the retentate stream passes through the micron waste filter 15.

The body of the disposable waste container 12 is made of a material that is structurally capable of holding the amount of wastewater expected, as well as being chemically resistant to that wastewater. The disposable waste container 12 is preferably made of polyethylene or polypropylene, having a thickness in the range 0.1 -1.0 mm, and can be transparent or semi-transparent to allow visibility of the interior by the user.

The micron waste filter 15 is a polypropylene mesh having a mesh pore size of 20pm, 25pm, 50pm or the like.

The filter unit 11 also comprises a porous filter 14, and is positioned in a first bunded housing 16. The porous filter 14 is an expanded porous foam material that allows flow through its pores at low pressure, with its structure interspaced with voids.

The first bunded housing 16 encloses a space into which the filter unit 11 is placed. The first bunded housing 16 is designed to have a sufficient volume that if the integrity of the filter unit 11 was compromised, then any wastewater and filtrate would be safely contained within the first bunded housing 16, and not leak from the clinical analyser wastewater treatment apparatus 10 and risk coming into contact with personnel in the vicinity of the apparatus 10.

The first bunded housing 16 includes handles 17 to facilitate its movement and handling. The filter unit 11 may be supported within the first bunded housing 16 if required.

The mass of the first bunded housing 16, and its contents increase in use and can be measured by a pressure measurement device 54 such as a load cell under the first bunded housing 16.

Figure 1 shows an inlet 18 for wastewater from a clinical analyser or the like, which is intended to be treated by the clinical analyser wastewater treatment apparatus 10 of the present invention. The clinical analyser wastewater inlet 18 is connected to the wastewater inlet 22 of the filter unit 11 by a pipe, tube or other conduit 20. Such incoming wastewater passes via an inlet downtube 21 inside the disposable waste container 12, to feed into the bottom of the disposable waste container 12 so as to limit the foaming that may otherwise occur.

The wastewater now in the disposable waste container 12 passes through the pores of the porous filter 14 before a first filtered wastewater stream is removed from the filter unit 11 by the action of the pump 30. A draw tube 24 connected to the porous filter 14 allows the passage of the filtered wastewater out of the filter unit 11 along the pump feed conduit 28 to the pump 30.

The pump 30 is connected by a sub-micron waste filter feed conduit 32 to the inlet 34 of the sub-micron waste filter 36. The sub-micron waste filter 36 has a membrane constructed as hollow fibres, with multiple fibres, often hundreds of fibres, in parallel passing up through a housing such that the inlet water passes along the inside of the fibres to a retentate outlet 44 of the sub-micron waste filter 36. Permeate, being water without the molecules larger than the pores in the membrane, passes through the membrane into a collection area between the fibres and the wall of the filter housing, and the pressure of the filtered water passing through the pores of the fibres pushes the filtered water out of a permeate port 38 of the sub-micron waste filter 36.

The pump 30 and sub-micron waste filter 36 are housed in their own second bunded housing 31 to provide further biosecurity should there be a leak from either component or an associated component or conduit as discussed above in relation to the first bunded housing 16. The filtered water stream passes from an outlet port 38 of the sub-micron waste filter 36 along a filtered water stream conduit 40 to a treated water outlet 42 of the clinical analyser wastewater treatment apparatus 10.

The retentate is the part of the wastewater that has not passed through the pores in the membrane of the sub-micron waste filter 36, and which includes molecules, including the microparticles, that were too large to pass through the membrane. As such, the retentate is now of greater concentration of those molecules and microparticles than the wastewater that entered the sub-micron waste filter 36, and it can be passed along a recirculation conduit 46 back to the filter unit 11. Optionally, the recirculation conduit 46 generates a back pressure so that the wastewater on the feed side of the sub-micron waste filter membrane is at a higher pressure than the filtrate, thereby causing a flow of filtrate through the membrane. Optionally this back pressure may be created by the use of a flow restrictor such as an orifice 58 in the retentate conduit 46. Optionally a retentate flush valve 68 may be included to reduce the back pressure at certain times, such as at start-up or at regular intervals, to flush the concentrate side of the membranes of any material that has become held there.

The recirculation conduit 46 fluidly connects to a retentate downtube 19 in the filter unit 11 via a retentate return port 48.

The retentate passes to the inside of the micron waste filter 15 via the retentate downtube 19. The retentate is then filtered by the micron waste filter 15, with particles and microparticles larger than the pores of the micron waste filter 15 being retained within the micron waste filter 15, before the filtered retentate enters into the same space in the disposable waste container 12 as the inlet analyser wastewater entering via inlet downtube 21. This completes a recirculation loop, and the wastewater in the disposable waste container 12 is now ready for further treatment by repeated recirculation and filtering as described above.

Optionally, a second sub-micron waste filter (not shown) can be used in series with the sub-micron waste filter 36, with the retentate leaving the first sub-micron waste filter 36 as described above, entering the second sub-micron waste filter, and being further concentrated in the same manner, before a further concentrated retentate is passed along the recirculation conduit 46 back to the filter unit 11. The permeates from both sub-micron waste filters can be combined in the filtered water stream conduit 40.

Figure 1 also shows a vent 52 to allow air to pass in or out of the disposable waste container 12 as it fills or empties, and to prevent it becoming over pressurised or a vacuum forming therewithin.

Figures 2 and 2a show parts of the apparatus 10 of figure 1 with greater detail, figure 2 being a cross section and figure 2a being a plan view.

Figures 2 and 2a show a filter unit manifold 50 as part of the filter unit 11 to provide the required support in the filter unit 11 for inlet and outlet connections to the non disposable parts of the treatment apparatus 10. The filter unit manifold 50 is designed to connect with a complementary treatment apparatus manifold 70 of the clinical wastewater treatment apparatus 10, to provide the required connections and passageways for the inlet, outlet and return ports 22, 26 and 48. A further port and spigot 78 may be included in the filter unit manifold 50 and the treatment apparatus manifold 70 as an overflow in case of excess flow from the clinical analyser to the apparatus 10.

Seals (not shown) such as o-rings may be used to provide seals at the junctions of the various ports in manifolds 50 and 70, i.e. between inlet port 22a, outlet port 26a and retentate return port 48a in treatment apparatus manifold 70 and inlet port 22b, outlet port 26b and retentate return port 48b in filter unit manifold 50. These ports also link to corresponding connection fittings 22c, 26c and 48c for attachment of the relevant conduits.

A first set of threads 12b near the outside top of the body of the disposable waste container 12 allow inside threads 50b on the filter unit manifold 50 to be securely attached to the disposable waste container 12. Meanwhile, a threaded securing collar 80 is also securely attachable to the top of the disposable waste container 12 using corresponding second set of threads 12a and 80a, to hold the treatment apparatus manifold 70 in place with the fluid unit manifold 50. Other or further locating devices may additionally or alternately be used. The filter unit manifold 50 and the treatment apparatus manifold 70 each include aligned vent portions 52a and 52b to form the vent 52 to allow air but not liquid to pass out of the filter unit 11 if required. The vent 52 incorporates a hydrophobic membrane which repels water as well as activated carbon to remove noxious chemicals that may be present in the vapour phase.

The micron waste filter 15 creates two areas within the disposable waste container 12; a first area 66 between the outside of the micron waste filter 15 where inlet wastewater and filtered retentate are located, and a second area 56 inside the micron waste filter 15 where unfiltered retentate water is located.

A pressure relief valve 72 is also incorporated in the filter unit manifold 50 and the treatment apparatus manifold 70 such that if the micron waste filter 15 becomes blocked, the increasing pressure of the unfiltered retentate 56 inside the micron waste filter 15 would cause a spring in the relief valve 72 to compress, and gas and/or liquid inside the micron waste filter 15 could pass into the second area 66 outside of the micron waste filter 15 via a route of 73a, 73b, 74b and 74a.

A retentate collector 76 may additionally be included in the micron waste filter 15 to help prevent foaming inside the micron waste filter 15 as the retentate is being returned into the filter unit 11 through inlets ports 48a, 48b, 48c.

The porous filter 14 is constructed with a filter body 60, being a disc of polyester foam of 30-60 pores per inch, and a holder 62 connected to the draw tube 24. The holder 62 is an inert plastic such as polyethylene or polypropylene.

An overflow 78 may additionally be included in the filter unit manifold 50 and the treatment apparatus manifold 70.

As the filter unit 11 operates, the concentration of the larger organic molecules and microparticles in the unfiltered retentate water in the first area 56 increases, due to return of the concentrated retentate from the sub-micron waste filter 36. As the concentration increases, larger organic molecules such as proteins become insoluble, and become removable on the surface and in the pores of the micron waste filter 15. Due to surface forces, microparticles can also become incorporated into the material removed on and in the micron waste filter 15.

The filter unit 11 and first bunded housing 16 is located upon the load cell 54 which determines the mass of the first bunded housing 16 and its contents, including the disposable waste container 12 and all of its contents.

In use, the disposable waste container 12 fills as the initial flow of clinical analyser waste fluid from outlet 18 increases, and reaches a fill limit due to the subsequent balance and effect of any further incoming clinical analyser wastewater effluent stream, the outgoing filtered water stream to the pump 30, and the recirculating retentate stream. The force acting upon the load cell 54 can be monitored and measured. Over time, the microparticles and organic matter that become trapped on the surface and in the pores of the micron waste filter 15 and the porous filter 14 increase the mass of the filter unit 11 , and therefore acting upon the load cell 54, and the increase in mass can be used to identify when the filter unit 11 requires changing.

The wastewater flow from the clinical analyser outlet 18 can be constant or irregular or intermittent. The treatment apparatus 10 can still operate during periods with no flow from the clinical analyser, so that the amount of water in the disposable waste container 12 decreases.

The minimum mass in the filter unit 11 , and hence the minimum force applied to the load cell 54, may also be monitored over time as an indicator of the efficiency or quality, generally the fouling, of the micron waste filter 15, and can be used as an indicator of when the filter unit 11 requires replacing.

Figure 2b shows the disposable filter unit 11 ready for disposal. For this, the securing collar 80 is unscrewed and removed. The treatment apparatus manifold 70 is then lifted from the filter unit manifold 50, and a threaded blanking cap 82 screwed onto the disposable water container 12, thus sealing all of the concentrated waste material in the disposable waste container 12, allowing the filter unit 11 to be safely removed from the remainder of the clinical wastewater treatment apparatus 10, ready for known clinical waste disposal, by such method as incineration. Optionally, a new filter unit 11 is installed, and the manifolds 50, 70 are reattached, to allow the method to restart.

In use, wastewater to be treated from a clinical analyser enters the clinical wastewater treatment apparatus 10 and fills the disposable waste container 12 via the inlet conduit 20 and the inlet downtube 21. The force on the load cell 54 is monitored, and when this reaches a value indicating that an amount of water and waste material has entered the filter unit 11, such that its mass has increased by a pre-determined amount, for example 5 kg, then the pump 30 and the retentate flush valve 68 are activated and wastewater is drawn through the porous filter 14 which removes macro-molecules that could block conduits or strands in the sub-micron waste filter 36, into the pump 30, the sub-micron waste filter 36 and via the retentate conduit 46 back to the filter unit 11.

After enough time to fill and flush the filter unit 11 , e.g. 15 seconds, the retentate flush valve 68 is de-energised and the wastewater flows through the retentate flow restrictor 58. This adds pressure to the concentrate side of the membrane(s) in the sub-micron waste filter 36 and permeate starts to pass across the membrane and along the filtered water conduit 40 for further treatment or to the treated water outlet 42 to be passed to a drain.

The pump 30 may be operated for a limited period before the cycle is allowed to repeat and/or monitoring of the load cell 54 may be used to stop the pump when the force on the load cell 54 has reduced by a pre-determined amount.

By a method of periodically, e.g. weekly, draining the filter unit 11 by use of the pump 30 until there is no change in the force on the load cell, a drained mass of the filter unit 11 can be determined. This will increase during use of the filter unit 11 and when this reaches a pre-determined amount an indicator such as an alarm can be raised informing the operator that the filter unit should be exchanged and the used filter unit 11 disposed of in line with local regulations.

The clinical wastewater treatment apparatus 10 may also use several further purification technologies in discrete or combined combinations or subsystems. Figures 3, 4a, 4b, 5, and 6 show technologies that can be incorporated into the treatment apparatus 10 in further embodiments of the invention. One or all of the technologies may be selected to be used to provide one or more further treatments of the filtered water stream 40 provided from the sub-micron waste filter 36 prior to its passage to the treated water outlet 42 of the treatment apparatus 10. Any or all of these may be used depending on the requirements of local legislation or the desire of the user.

Figure 3 shows an anodic oxidation cell subsystem 110. The filtered water 138 from the sub-micron waste filter 36 is passed through an anodic oxidation cell feed conduit 140 into the anodic oxidation chamber 141 containing one or more anodes 144 and one or more cathodes 146 where it is treated prior to its passage along an anodic oxidation cell outlet conduit 148 to its exit from the anodic oxidation chamber subsystem 142 passing to either another treatment subsystem or exiting from the clinical wastewater treatment apparatus 10.

Figure 4a shows an ultraviolet irradiation cell subsystem 210. The filtered water 238 from the sub-micron waste filter 36 is passed through a ultraviolet (UV) irradiation cell feed conduit 240 into an ultraviolet irradiation chamber 241 where ultraviolet irradiation is passed into the water from UV emitting devices 244, light emitting diodes (LEDs), at a wavelength selected to interact with and deactivate microbiologically active components such as bacteria and viruses in the water. The UV emitting devices 244 are held in a separate section of the UV irradiation cell subsystem 210 and the UV passes into the UV irradiation chamber through a quartz glass 246 between the UV emitting devices 244 and the irradiation chamber 241. Once treated the water exits the UV irradiation chamber subsystem 210 along an UV irradiation cell outlet conduit 248 to the exit from the ultraviolet irradiation subsystem 242 passing to either another treatment subsystem or exiting from the clinical wastewater treatment apparatus 10.

Figure 4b shows an alternative ultraviolet irradiation cell subsystem 410. The filtered water 438 from the sub-micron waste filter 36 is passed through an ultraviolet (UV) irradiation cell feed conduit 440 into one or more ultraviolet irradiation chambers 441 where ultraviolet irradiation is passed into the water from an UV emitting device 444, preferably an excimer lamp or mercury lamp, at a wavelength selected to degrade micropollutants in the water. The UV emitting devices are held in a separate section of the UV irradiation cell and the UV passes into the UV irradiation chamber through a quartz glass 448 between the UV emitting devices and the irradiation chamber 441. Once treated the water exits the UV irradiation chamber along an UV irradiation cell outlet conduit 450 to the exit from the ultraviolet irradiation subsystem 442 passing to either another treatment subsystem or exiting from the clinical wastewater treatment apparatus 10.

Figure 5 shows a gas/liquid contactor subsystem 310. Gas/liquid contactors are known in the art and may be used to reduce the pH of the wastewater to a desired level. The filtered water 338 from the sub-micron waste filter 36 is passed through a gas/liquid contactor feed conduit 340 into the gas/liquid contactor 341 containing one or more hydrophobic fibres 344, multiple hollow fibres of hydrophobic membrane. While in the hollow fibres 344, carbon dioxide introduced into the gas/liquid contactor 341 via gas feed line 348 passes through the pores in the hydrophobic membrane 344 and enters the water reducing its pH. The water passes through the centre of the hollow fibres until it passes from the gas/liquid contactor through a gas/liquid contactor outlet conduit 346 to the exit from the gas/liquid contactor subsystem 342 passing to either another treatment subsystem or exiting from the clinical wastewater treatment apparatus 10. A gas exhaust 350 may be used to vent unused carbon dioxide or to exhaust gases and volatile molecules that have passed from the liquid into the gas phase. This may particularly occur if used after anodic oxidation and scrubbing of the exhaust may be required to prevent volatile molecules from entering the atmosphere.

Recirculation around the gas/liquid contactor may take place repeatedly thus allowing greater treatment of the water or the use of smaller apparatus.

Monitoring of the pH of the water exiting the gas/liquid contactor may take place and comparison of the pH with desired levels used to control the amount of carbon dioxide added, or control any operation of recirculation and discharge.

Figure 6 shows a foam fractionation subsystem 510. The filtered water 538 from the sub-micron waste filter 36 is passed through a foam fractionation feed conduit 540 into the foam fractionation chamber 541 containing one or more spargers 544 where gas, preferably air, can be introduced via gas feed line 546. As water mixes with the supplied gas, foam rises through the foam fractionation chamber and exits via foam conduit 560 to foam collection device or chamber 558. Preferably a foam destabilisation material 559 is included therein to break down the foam and reduce its volume. The remainder of the liquid passes out of the foam fractionation subsystem via foam fractionation chamber outlet conduit 548 to the exit from the foam fractionation subsystem 542 passing to either another treatment subsystem or exiting from the clinical wastewater treatment apparatus 10.

The present invention provides apparatus and methods to treat a clinical wastewater effluent stream, and to safely capture the hazardous materials therein, such as the remnants of the biological samples that have been tested in the analyser, and in a manner that also protects operatives and users. Such captured material can then be safely disposed of as clinical waste, and the filtered water passed to a normal drain.

Claims

1 . A clinical wastewater treatment apparatus to treat a clinical wastewater effluent stream, comprising: a filter unit having

- a clinical wastewater effluent stream inlet,

- a fluid outlet, and

2. A clinical wastewater treatment apparatus as claimed in claim 1 further comprising a first bunded housing to support the filter unit, and wherein the filter unit is separable from the housing.

3. A clinical wastewater treatment apparatus as claimed in any one of the preceding claims further comprising a second bunded housing to house the pump and the sub-micron waste filter.

4. A clinical wastewater treatment apparatus as claimed in any one of the preceding claims wherein the filter unit has lifting handles.

5. A clinical wastewater treatment apparatus as claimed in any one of the preceding claims wherein the filter unit includes a filter unit manifold having the clinical wastewater effluent stream inlet and the fluid outlet.

6. A clinical wastewater treatment apparatus as claimed in claim 5 wherein the clinical wastewater treatment apparatus has a treatment apparatus manifold having ports to match with the filter unit manifold.

7. A clinical wastewater treatment apparatus as claimed in claim 6 wherein the waste container has a first threaded seal with the filter unit manifold.

8. A clinical wastewater treatment apparatus as claimed in any one of claims 5 to 7 wherein the waste container has a second threaded seal with either a manifold securing collar or a blanking cap.

9. A clinical wastewater treatment apparatus as claimed in any one of the preceding claims wherein the filter unit further includes an internal outlet feed for the fluid outlet of the filter unit, the internal outlet feed having a porous filter.

10. A clinical wastewater treatment apparatus as claimed in claim 9 wherein the porous filter is a millimetre or sub-millimetre foam filter, optionally a pore size in the range 100 -1000 pm.

11. A clinical wastewater treatment apparatus as claimed in any one of the preceding claims wherein the waste container has an in-use volume in the range of 2-20 litres.

12. A clinical wastewater treatment apparatus as claimed in any one of the preceding claims wherein the waste container is a plastics material selected from the group comprising: polyethylene, polypropylene, acrylic, polycarbonate, polyvinyl chloride, polyethylene terephthalate, acrylonitrile butadiene styrene, and combinations of same.

13. A clinical wastewater treatment apparatus as claimed in any one of the preceding claims wherein the micron waste filter comprises a woven or a mesh material.

14. A clinical wastewater treatment apparatus as claimed in claim 13 wherein the woven or mesh material is selected from the group comprising: polyethylene, polypropylene, nylon, acrylic, polycarbonate, polyvinyl chloride, polyethylene terephthalate, acrylonitrile butadiene styrene, and combinations of same.

15. A clinical wastewater treatment apparatus as claimed in claim 13 or claim 14 wherein the micron waste filter comprises a mesh material having a pore size in the range 10-100 pm.

16. A clinical wastewater treatment apparatus as claimed in any one of the preceding claims further comprising means to determine the capacity of the filter unit over time.

17. A clinical wastewater treatment apparatus as claimed in claim 16 comprising a device for measuring the pressure of the flow from the pump.

18. A clinical wastewater treatment apparatus as claimed in claim 16 comprising a device for measuring the weight of the filter unit over time.

19. A clinical wastewater treatment apparatus as claimed in any one of the preceding claims wherein the sub-micron waste filter comprises a spiral wound membrane or a hollow fibre membrane.

20. A clinical wastewater treatment apparatus as claimed in any one of the preceding claims wherein the sub-micron waste filter is able to filter microparticles from a stream.

21. A clinical wastewater treatment apparatus as claimed in any one of the preceding claims wherein the filter unit further comprises a pressure relief valve between the internal and external sides of the micron waste filter.

22. A clinical wastewater treatment apparatus as claimed in any one of the preceding claims wherein the filter unit is detachable from the remainder of the clinical wastewater treatment apparatus, and the filter unit is thereafter disposable as clinical waste.

23. A clinical wastewater treatment apparatus as claimed in any one of the preceding claims wherein the micron waste filter has an elongate shape, and wherein the filter unit includes a waste inlet conduit extending from one end of the filter unit and substantially towards the other end of the waste filter.

24. A clinical wastewater treatment apparatus as claimed in any one of the preceding claims further including one or more of the group comprising: a downstream ultraviolet disinfection unit, a downstream ultraviolet oxidation unit, a downstream anodic oxidation unit, a downstream gas/liquid pH adjustment unit, and a foam fractionation unit.

25. A method of treating a clinical analyser wastewater effluent stream containing microparticles and organic molecules, comprising at least the following steps in any order:

26. A method as claimed in claim 25 further comprising the step of passing the filtered clinical analyser wastewater stream through a porous filter within the filter unit, optionally wherein the porous filter is a millimetre or sub-millimetre foam filter having a pore size in the range 100 -1000 pm, prior to step (c).

27. A method as claimed in claim 25 or claim 26 further comprising prior to any of steps (b) to (e), the step of initially passing the clinical analyser wastewater effluent stream into the filter unit through a clinical wastewater effluent stream inlet to partly, substantially or wholly fill the filter unit.

28. A method as claimed in any one of claims 25 to 29, further comprising the step of further filling the filter unit with a clinical analyser wastewater effluent stream during any one or more of steps (b) to (e).

29. A method as claimed in any one of claims 25 to 29, wherein the operation of the pump in step (c) is dependent on the volume, the weight, or both the volume and weight, of the filter unit.

30. A method as claimed in any one of claims 25 to 29, wherein the operation of the pump in step (c) is dependent on the pressure of the flow from the pump.

31. A method as claimed in any one of claims 25 to 30, further comprising determining the capacity of the filter unit over time.

32. A method as claimed in claim 31 comprising repeating steps (b) to (e) until the capacity of the filter unit reaches a pre-determined value, and then further comprising the steps of;

- stopping the pump,

- detaching the filter unit from the clinical wastewater treatment apparatus,

- optionally adding a blanking cap onto the filter unit, and

- disposing of the filter unit as clinical waste.

33. A method as claimed in any one of claims 31 to 32, further comprising determining the capacity of the filter unit over time by either measuring the pressure of the flow from the pump, or measuring the weight of the filter unit over time, or both.

34. A method as claimed in any one of claims 25 to 33 further comprising treating the filtered water stream with one or more of the following in any order: ultraviolet irradiation, anodic oxidation, gas/liquid pH adjustment, and foam fractionation.

35. A method as claimed in any one of claims 25 to 34 using the clinical wastewater treatment apparatus as defined in any one of claims 1 to 24.

36. A method of collecting and disposing of organic molecules and microparticles in a clinical analyser wastewater effluent stream, comprising at least the steps of:

(f1) passing the filtered water stream of step (c1) to a drain;

(g1) repeating steps (b1) to (f1);

(hi) determining an end use of the filter unit and stopping the pump; and

37. A method as claimed in claim 36 further comprising the step of passing the filtered clinical analyser wastewater stream through a porous filter within the filter unit, optionally wherein the porous filter is a millimetre or sub-millimetre foam filter having a pore size in the range 100 -1000 pm, prior to step (b1).

38. A method as claimed in any one of claims 36 to 37 further comprising the step of replacing the detached filter unit with a new filter unit.

39. A method as claimed in any one of claims 36 to 38 further comprising measuring the capacity of the filter unit over time, and operating step (b1) according to the capacity of the filter unit.

40. A method as claimed in claim 39 comprising measuring the weight of the filter unit, and operating step (b1) according to the weight of the filter unit.

41. A method as claimed in any one of claims 36 to 40 further comprising using the weight measurement of the filter unit to determine the operation of step (hi).

42. A method as claimed in any one of claims 36 to 41 using the clinical wastewater treatment apparatus as defined in any one of claims 1 to 24.